You can find the explanation in the first words of the first sentence:
"European jet maker Airbus Group SE is locked in a dispute with U.S. regulators over the safety of lithium-ion batteries installed on its latest model, according to people familiar with the details.".
Also, the US agency is finding a foreign manufacturer an easier target to create an inroad into regulating the battery issue - less lobbying. It's similar to the way the US banned *imports* of automatic weapons to combat gun crime, without offending the domestic gun lobby. One can recall that Boeing was allowed to self-certify its 787 battery system, so clearly domestic manufacturers enjoy a certain leeway on safety issues ... from domestic regulators.